Several studies have reported differences in long-range temporal correlations of EEG oscillations between depressed and nondepressed individuals. The question remains unsolved whether these differences are also linked to negative emotion regulation strategies that configure a depressive style. In this study we applied detrended fluctuation analysis to the amplitude envelope of broad band and narrow band (theta and alpha) spontaneous EEG oscillations of a sample (N = 56) of young nondepressed adults to whom several emotion regulation and depression questionnaires were administered. Linear positive correlations between the scaling exponents of both broad band and theta band oscillations and negative emotion regulation strategies and depression scores were found. These results suggest that previously found differences between depressed and nondepressed individuals may exist before depression manifests, as differences could be linked to a negative emotion regulation style that in some cases could lead to the development of a depressive disorder.

In this case study the electroencephalographic (EEG) activity of a 23 years old snake phobic patient was recorded one week before treatment, one week after successful one-session exposure therapy, and one year later. EEG recordings were obtained at rest and during exposure to pictures of snakes, pictures of equivalent arousing power, and emotionally neutral images, all of them taken from the International Affective Pictures System. Measures of brain dynamics were sample entropy (SampEn) for each EEG signal/channel and phase synchronization between pairs of EEG channels. Results showed dramatic changes in both measures one week after treatment: SampEn increased and phase synchrony decreased at all sites and pairs of channels respectively. At follow-up, however, we found patterns of entropy and synchrony change across conditions that were similar to the pre-treatment ones, while the patient did not report any fear at all. Despite the limitations of single case studies, these results suggest that the exposure-induced changes in EEG entropy and synchronization are large but transient. The transient increase of the brain’s flexibility could be one of the working neurophysiological mechanisms of exposure therapy.

Phylogenetic fears involve stimuli representing a real or potential threat to the species¿ evolutionary ancestors. We tested whether individuals with a phylogenetic fear (spider phobics, n = 17) differed in EEG general activity (delta band power) of the oldest brain system and in complexity from individuals with a non-phylogenetic fear (flight phobics, n = 15) during eyes open and eyes closed resting states. Delta band power was higher during the eyes-closed condition at central sites FZ, CZ and PZ as well as at frontal sites FP1, FP2, and F4. No differences existed in the upper bands theta, alpha, and beta. The EEG complexity was significantly lower among individuals with spider phobia. Differences were found under both eyes closed and eyes open conditions at FZ, F4, CZ, and C4. Lower complexity was also found at PZ and O2 during eyes open. In general, the results of this ex post facto study lend support to the hypothesized prevalence of slow oscillations in phylogenetic fears. Furthermorethese results show that the EEG output of spider phobic participants is less complex than the output from flight phobic participants. The prevalence of slow brain oscillations and the lowered EEG complexity could be interpreted as traces of phylogenetic fears.